With Britain enduring hailstones, temperatures below 10C and records revealing the UK's "worst" spring for 30 years, Public Health England has, with impeccable timing and without irony, published its heatwave strategy for 2013.

The report, published annually since 2004, possibly takes the precautionary principle to an unattained level.

The first chapter of the 46-page strategy asks the challenging question: "Why is this strategy necessary?" Despite valiant efforts, though, it struggles to answer its own question. But it warns readers: "While we're enjoying the balmy days of summer, we should not forget that the temperature can get too high, that it can become uncomfortably hot, and, for some, it can become dangerously hot."

As concerned readers rush to turn off the central heating, the strategy warns: "The rise in mortality as a result of very warm weather follows very sharply – within one or two days of the temperature rising. This means that … by the time a heatwave starts the window of opportunity for effective action is very short indeed; therefore advanced planning and preparedness is essential."

The report was first drafted in the wake of the pan-European heatwave of 2003, and in a possible sign that its value is under question has been recently revamped to blend with the cold weather strategy.

As with all government strategies, it is written in best Whitehallese and without much sign the author has ever looked out of the window.

It suggests: "The Heatwave Plan is underpinned by the Heat-Health Watch alert system which has been developed with the Met Office to alert key stakeholders to the likelihood of severe hot weather in different parts of the country, so they can take appropriate action."

"Key elements of the plan include heatwave and summer preparedness, communicating with the public and working with service providers.

It advises: "There should be a local heat-related health information plan – specifying what is communicated, to whom, when and why."

The strategy has been published in the week when Met Office figures suggest that spring 2013 (March, April and May) is on course to be the coldest spring in the UK since 1979.

Data from 1 March until 15 May has been extrapolated with an assumption of average temperatures for the remainder of May.

The estimate suggests the average temperature this spring will be around 6.1C, which would place it as the sixth coldest spring in records that go back to 1910.

Top tips include keeping out of the sun between 11.00am and 3.00pm.

• If you have to go out in the heat, walk in the shade, apply sunscreen and wear a hat and light scarf

• Close curtains that receive morning or afternoon sun. However, care should be taken with metal blinds and dark curtains, as these can absorb heat – consider replacing or putting reflective material in-between them and the window space